1. Field of the Invention
The invention relates to compositions and articles containing a polymer matrix and an immobilized active liquid therein, as well as methods of making and using the same.
2. Description of the Related Art
The curing and/or cross-linking of polymeric systems, for example epoxy systems, is described in textbooks and industrial handbooks such as “Handbook Of Epoxy Resins” by Henry Lee and Kris Neville (McGraw Hill, 1967), “The Epoxy Formulators Manual” by the Society of Plastics Industry, Inc. (1984), and the Encyclopedia of Science and Technology (Kirk-Othmer, John Wiley & Sons, 1994). Until recently, curing such systems and others related thereto in a manner capable of immobilizing active liquids, such as those having and/or containing fragrance, has been very difficult, especially when durability and performance under a dynamic range of operation conditions are required from such systems.
For example, JP 032558899A requires the use of a solid powder system, while JP07145299 requires the use of a pre-formed urethane-containing epoxy resin cross-linked in the absence of a polyamine and/or an active liquid containing a perfume. Further, the above-mentioned JP references refer specifically and only to fragranced articles, such as air fresheners. Because of this narrow goal to make such articles, the reaction and reaction products described therein fail to have a dynamic range of performance capabilities. Moreover, they fail to provide a product that is durable in the absence of a support. Therefore, a need arises for controllable reaction conditions that yield dynamic reaction products containing durable matrices capable of immobilizing any and/or all types of active liquids therein.
Compositions such as fragrance objects, even more specifically air fresheners, are well known devices that release a fragrance into the air of a room of a house, area of a public building (e.g. a lavatory) or the interior of a car to render the air in that area more pleasing to the occupant. Only substantially non-aqueous gels, for example the thermoplastic polyamide-based products described in U.S. Pat. Nos. 6,111,655 and 6,503,577 and the thermo-set poly(amide-acid)s of U.S. Pat. No. 5,780,527 and of U.S. Pat. No. 6,846,491, are homogeneous, transparent solids that can be easily charged, when in liquid form, to a mold and thus made into a visually attractive solid shape without the use of a means of support. However, during preparation of thermoplastic gels, the components must be heated to a temperature above the gelation temperature of the mixture, a process detrimental to the volatile and sometimes temperature sensitive active liquid such as fragrance, pesticide or surfactant. During storage or use, these gels must not be exposed to low temperatures because they can turn unattractively cloudy. Furthermore, these gels must not be exposed to high temperatures because they will turn liquid, losing their shape or leaking from their container. These drawbacks are serious for air fresheners necessarily exposed to a dynamic range of temperatures, such as car interior fresheners. The latter are often exposed to low temperatures in winter and temperatures in excess of 110° F. on summer days when the car is parked in direct sunlight. In addition, thermoplastic gels are soft solids that are easily deformed if scraped, dropped, poked, or wiped. Thus, these conventional gels do not provide compositions and/or articles that are readily durable and capable of operating at a wide range of operating parameters.